Abrasive articles, such as coated abrasive articles, are used in various industries to abrade work pieces by hand or by machine processes, such as by lapping, grinding, or polishing. Machining utilizing abrasive articles spans a wide industrial and consumer scope from optics industries, automotive paint repair industries, and metal fabrication industries to construction and carpentry. Machining, such as by hand or with use of commonly available tools such as orbital polishers (both random and fixed axis), and belt and vibratory sanders, is also commonly done by consumers in household applications. In each of these examples, abrasives are used to remove surface material and affect the surface characteristics (e.g., planarity, surface roughness, gloss) of the abraded surface. Additionally, various types of automated processing systems have been developed to abrasively process articles of various compositions and configurations.
Surface characteristics include, among others, shine, texture, gloss, surface roughness, and uniformity. In particular, surface characteristics, such as roughness and gloss, are measured to determine quality. Typically, defects in a surface are removed by first sanding with a coarse grain abrasive, followed by subsequently sanding with progressively finer grain abrasives, and even buffing with wool or foam pads until a desired smoothness is achieved. Hence, the properties of the abrasive article used will generally influence the surface quality.
In addition to surface characteristics, users are sensitive to cost related to abrasive operations. Factors influencing operational costs include the speed at which a surface can be prepared and the cost of the materials used to prepare that surface. Typically, a user seeks cost effective materials having high material removal rates.
However, abrasives that exhibit high removal rates often exhibit poor performance in achieving desirable surface characteristics. Conversely, abrasives that produce desirable surface characteristics often have low material removal rates. For this reason, preparation of a surface is often a multi-step process using various grades of abrasive. Typically, surface flaws (e.g., scratches) introduced by one step are repaired (e.g., removed) using progressively finer grain abrasives in one or more subsequent steps. Therefore, abrasives that introduce scratches and surface flaws result in increased time, effort, and expenditure of materials in subsequent processing steps and an overall increase in total processing costs.
In an effort to achieve certain abrasive performance characteristics (e.g., cut rate, surface finish, abrasive grain retention, mechanical stress resistance, thermal resistance, and solvent resistance) under demanding conditions (e.g., high-speed abrading and grinding), conventional abrasive articles typically incorporate components, such as polymer binder systems, abrasive grains, and backing materials that contain environmentally harmful chemicals or are themselves environmentally unfriendly due to a lack of biodegradability, recyclability, or re-usability.
For instance, phenol-formaldehyde resins (i.e., novolac and resole resins) and urea-formaldehyde resins are commonly encountered as abrasive binder compositions in conventional abrasive articles. At least one drawback of these phenol-formaldehyde and urea-formaldehyde resins is that they contain formaldehyde, which can be harmful to people and the environment.
Although various efforts have been made to replace various components of abrasive articles, there continues to be a demand for improved, cost effective, abrasive articles, processes, and systems that can promote and achieve efficient abrasion and improved surface characteristics, but that are at the same time environmentally friendly.
The use of the same reference symbols in different drawings indicates similar or identical items.